Hypodermic syringes and needles are used for injections and drawing blood in medical and veterinary settings throughout the world. In health care settings large numbers of patients require injections or blood sampling services in short periods of time. The use of large numbers of hypodermic syringes and needles under the constraints imposed by typical health care environments, inevitably, leads to health care professionals accidentally pricking themselves. or others with a previously used needle, or alternatively, coming into contact with fluids which have leaked from a syringe, the needle associated with which was not capped after use. The recent AIDS epidemic has heightened awareness of the potentially devastating effect such accidents can have. Not only can patients become mortally infected by a needle prick, or contact with fluid leaked from a syringe but health care professionals can as well. A needle prick can end the career of a health care professional, which career took years to nurture, in but a second. The inevitable nature of such occurrences has led creative people to design new systems and propose methods of use of specialty hypodermic syringes and needles, or adaptations thereof, which have as their focus the minimization of the risk that unintended needle pricks and/or fluid spills from used systems with uncapped needles will occur.
In recent years a number of patents have issued, the inventions in which teach means by which the risk alluded to can be lessened. In evaluating said inventions, a number of factors must be considered. The foremost factor is, of course, the likelihood of success in achieving a lessened risk of unintended needle pricks and/or fluid spills from used systems. Generally, such likelihood is reduced in inverse proportion to the level of difficulty involved in practicing the system or method of a given invention. The more difficult it is to use an invention, the less likely it is to be successful or even used. Another consideration is the complexity of an invention per se. Accompanying complexity is the consideration of the cost of manufacturing an invention.
An ideal system for lessening the risk of accidental needle pricks and fluid spills from used syringes would be very easy and economical to manufacture and extremely simple to use.
A study of existing prior patents in relevant areas show that many prior inventions which provide means for securing a needle after use, are complex to manufacture (hence potentially expensive) and/or operate, (e.g. U.S. Pat. No. 4,631,057 to Mitchell; U.S. Pat. No. 4,425,120 to Sampson; U.S. Pat. No. 4,666,435 to Braginetz; U.S. Pat. No. 4,664,654 to Strauss; U.S. Pat. No. 4,693,708 to Wanderer; U.S. Pat. No. 2,674,246 to Bower; U.S. Pat. No. 4,681,567 to Masters; U.S. Pat. No. 4,655,751 to Harbaugh; and U.S. Pat. No. 4,702,738 to Spencer).
A study of existing patents in the relevant area also shows that many prior inventions which provide means of securing a needle after use require two hands to use effectively, (e.g., U.S. Pat. No. 4,631,057 to Mitchell; U.S. Pat. No. 4,573,976 to Sampson; U.S. Pat. No. 4,425,120 to Sampson; U.S. Pat. No. 4,666,435 to Braginetz; U.S. Pat. No. 4,659,330 to Nelson; U.S. Pat. No. 4,693,708 to Wanderer; U.S. Pat. No. 4,681,567 to Masters; U.S. Pat. No. 4,655,751 to Harbaugh; U.S. Pat. No. 4,702,738 to Spencer; and U.S. Pat. No. 2,571,653 to Bastien). The necessity of using two hands to operate a mechanism is a definite drawback. An ideal mechanism should be easy to operate with one hand, perhaps by motion imparted by a user's thumb as a syringe rests on the surface formed by the fingers of the same hand.
Some prior inventions involve a needle guard which must be rotated to be used, (e.g. U.S. Pat. No. 4,425,120 to Sampson; U.S. Pat. No. 4,666,435 to Braginetz; U.S. Pat. No. 4,693,708 to Wanderer; U.S. Pat. No. 2,674,246 to Bower; U.S. Pat. No. 4,702,738 to Spencer). In addition, some needle guards are free to rotate around a syringe even though rotary motion is not required for operation (e.g., U.S. Pat. No. 4,631,057 to Mitchell; U.S. Pat. No. 4,573,976 to Sampson; U.S. Pat. No. 4,655,751 to Harbaugh; U.S. Pat. No. 2,571,653 to Bastien). It is not necessary to protect a needle point that a shield rotate, rather a shield must move longitudinally along a needle to accomplish the task. It is doubtful if any benefit provided by the rotational aspect of the shield justifies the added complexity in construction, and potential for blocking the ability to observe the contents of a syringe by the rotational motion of the shield. Further examination of existing patents show that view of liquid in a syringe taught in said patents is by way of two layers of plastic or glass, (e.g., U.S. Pat. No. 4,631,057 to Mitchell; U.S. Pat. No. 4,573,976 to Sampson; U.S. Pat. No. 4,425,120 to Sampson; U.S. Pat. No. 4,666,435 to Barginetz; U.S. Pat. No. 4,693,708 to Wanderer; U.S. Pat. No. 2,674,246 to Bower; U.S. Pat. No. 4,681,567 to Masters; U.S. Pat. No. 4,655,751 to Harbaugh; U.S. Pat. No. 4,702,738 to Spencer; and U.S. Pat. No. 2,571,653 to Bastien). Any obstruction of view in addition to a syringe wall, of the liquid in a syringe is an undesirable factor. Such obstruction simply serves no useful purpose.
Further study of existing patents show some inventions require springs in their construction (e.g., U.S. Pat. No. 4,664,654 to Strauss; and U.S. Pat. No. 2,674,246 to Bower). Springs are added complexity and it would be preferable if any "spring" required could be a natural consequence of the design of an inventions parts so as to include such naturally, perhaps in the form of molded plastic parts with physical "memory".
Many existing inventions also provide needle shields which are open at their end. That is the needle is inside a tubular structure or equivalent which is not closed at its end. Examples are the inventions in U.S. Pat. No. 4,631,057 to Mitchell; U.S. Pat. No. 4,573,976 to Sampson; U.S. Pat. No. 4,425,120 to Sampson; U.S. Pat. No. 4,666,435 to Braginetz; U.S. Pat. No. 4,664,654 to Strauss; U.S. Pat. No. 4,693,708 to Wanderer; U.S. Pat. No. 4,681,567 to Masters; U.S. Pat. No. 4,655,751 to Harbaugh; and U.S. Pat. No. 2,571,653 to Bastien). Two inventions provide caps to cover open ended needle shields, (e.g., U.S. Pat. No. 2,674,246 to Bower and U.S. Pat. No. 4,702,738 to Spencer). Except for these inventions, all those with open ended needle shields can allow fluid to leak out of a syringe. The obvious disadvantage of such is that one could come into contact with fluid which has leaked from a syringe and be infected through a pre-existing wound. A safe needle guard should provide for preventing leakage from a syringe without requiring a dangerous recapping process in which two hands are required to perform.
It should also be noted that of the inventions alluded to, only that in U.S. Pat. No. 4,664,654 to Strauss does not require that a collar be placed around the syringe itself to achieve its system, and only the invention in U.S. Pat. No. 4,681,587 to Masters provides for a clear syringe when the needle shield is mounted on a syringe. Both inventions require two hands to operate as well.
A system which would provide for securing syringe needles to prevent accidental needle pricks and which would prevent fluid leakage from syringes when in place (i.e., closed end on needle when in place), and which would provide clear view of fluid in a syringe through one layer (i.e., no collar required on a syringe) of plastic or glass both prior to and after securing a needle; and which provides spring to ensure needle securement by clever design of elements rather than by use of springs per se; and which does not require, or even allow, needle guard rotation; or require more than one hand to operate; and which is simple and economical to manufacture would be of great utility. Such a system is taught herein, directly.